1. Field of the Invention
The present invention relates to an apparatus and method for inspecting an anti-lock brake system provided in a two-wheeled vehicle and a front and rear wheel interlocking brake system including the anti-lock brake system.
2. Description of the Related Art
Conventionally, apparatuses for inspecting actuation of an anti-lock brake system (hereinafter referred to as ABS) and a front and rear wheel interlocking brake system (hereinafter referred to as CBS) of a two-wheeled vehicle are known (see Japanese Patent Laid-Open No. 2001-281108, for example).
The inspecting apparatus comprises one pair of support rollers (front wheel support rollers) on which a front wheel is situated and supported and one pair of support rollers (rear wheel support rollers) on which a rear wheel is situated and supported, wherein one of the front wheel support rollers and one of the rear wheel support rollers are coupled with each other by coupling means to synchronously rotate. The surface of each roller is formed of a low friction material. In addition, on the other front wheel support roller and the other rear wheel support roller, rotational speed detecting means for detecting rotational speed of the respective roller are provided in a coupled manner. Further, a drive motor is coupled to one of the rear wheel support rollers via a clutch.
In the inspecting apparatus configured in this manner, when the ABS of the two-wheeled vehicle is inspected, the front wheel and the rear wheel of the test vehicle are firstly situated on one pair of the front wheel support rollers and one pair of the rear wheel support rollers, respectively and the rear wheel support roller is rotated by the drive motor. Thereby, both rear wheel support rollers rotate via the rear wheel and this rotation is further transmitted via one front wheel support rollers to the front wheel and the other front wheel support roller, so that all rollers rotate synchronously.
Then, when the rotational speed of the roller obtained from the rotational speed detecting means reaches a predetermined speed, the clutch is brought into the OFF state to disconnect the one rear wheel support roller from the drive motor and an operator fully inputs the brake in this state. Accordingly, each roller which is disconnected from the driving force of the drive motor by means of the clutch continues to inertially rotate, while the rotational speed of each roller gradually decreases due to deceleration by the brake input. Because the surface of each roller is formed of the low friction material, slip occurs between the wheels of the two-wheeled vehicle and the respective rollers so that the ABS actuates to perform pumping brake action. Thereafter, each roller stops by actuation of the brake and then pass/failure determination of the ABS performance is performed by comparing the stop time and a value which is predetermined in actual driving measurement.
Also when the CBS of the two-wheeled vehicle is inspected by the conventional inspecting apparatus, as is the case of the ABS inspection, one of the brakes (e.g. the rear wheel brake) is inputted and the other brake (e.g. the front wheel brake) is interlocked with the former, and pass/fail determination of the CBS performance is performed by comparing the stop time of each roller and a value which is predetermined in actual driving measurement.
However, in the ABS inspection by the conventional inspecting apparatus, the determination result cannot be obtained unless rotation of each support roller stops after the brake input and therefore it is disadvantageous that the inspection time is relatively long. Further, because actuation check of the CBS is performed with physical feeling of the operator, the operator is required to be skilled in the task and it is disadvantageous that high inspection accuracy can not be expected.
Therefore, it has been proposed that increase/decrease in rotational speed of the wheel caused by repetition of ON/OFF of the brake during the ABS actuation is measured to determine a waveform based on this measured data and pass/fail determination of the ABS and CBS is performed by determining whether a part of the waveform is within a predetermined range in a predetermined elapsed time or not (see Japanese Patent Laid-Open No. 2003-254870, for example). According to this approach, the inspection time can be significantly reduced because inspection of the brake system can be performed without sampling the elapsed time from the brake input until the wheel stops.
However, also in this approach, one of the front wheel support rollers and one of the rear wheel support rollers are coupled with each other by the coupling means to synchronously rotate. Therefore, particularly in the CBS inspection, even if increases/decreases in the rotational speeds of the front wheel and the rear wheel are measured, it is disadvantageously not clear whether the increases/decreases in the rotational speeds of both wheels results from the CBS actuation or results from the braking force transmitted from one wheel to the other wheel through the coupling means.
Thus, in some two-wheeled vehicles provided with the CBS, the braking forces may be differently distributed in interlocking the rear wheel brake and the front wheel brake. In such a two-wheeled vehicle, for example, if the braking force for the front wheel brake actuation by the CBS is set to be remarkably smaller than that for the rear wheel brake at the time of fully inputting the rear wheel brake, it is conceivable that the increase/decrease in the rotational speed of the front wheel may not result from the actual actuation by the front wheel brake, but from the effect of the braking force of the rear wheel transmitted to the front wheel through the coupling means. If the pass/fail determination is performed based on the measured data which is sampled in such a condition, the interlock by the CBS can be determined to be successful even though the front wheel brake does not actuate, which results in a disadvantage of reducing the inspection accuracy.
To solve the above described disadvantages, it is an object of the present invention to provide an apparatus and a method for inspecting a brake system of a two-wheeled vehicle, which not only can reduce the time required for each inspection of the two-wheeled vehicle to efficiently perform the inspection of the two-wheeled vehicle, but also remarkably improve the inspection accuracy.